Standard temperature reference.
Freezing and boiling points of common substances, comfort and cooking temperatures, body temperatures, weather extremes — everything on one chart, in Fahrenheit and Celsius.
The chart
| Temperature (°F) | Temperature (°C) | Reference point |
|---|---|---|
| −459.67 °F | −273.15 °C | Absolute zero — no thermal motion. Defined exactly. |
| −320.5 °F | −195.8 °C | Liquid nitrogen boiling point (at 1 atm) |
| −109.3 °F | −78.5 °C | Dry ice (solid CO₂) sublimation |
| −40 °F | −40 °C | F and C meet — the only point where Fahrenheit equals Celsius |
| −128.6 °F | −89.2 °C | Coldest natural temperature on Earth (Vostok Station, Antarctica, 1983) |
| −4 °F | −20 °C | Home freezer (typical) |
| 0 °F | −17.8 °C | Original Fahrenheit zero (saturated salt water) |
| −37.9 °F | −38.83 °C | Mercury freezes |
| 14 °F | −10 °C | Standard freezer temperature |
| 32 °F | 0 °C | Water freezes (1 atm) |
| 34-38 °F | 1-3 °C | Refrigerator (recommended 1-4 °C / 34-40 °F) |
| 40 °F | 4 °C | Refrigerator typical / cold air mass |
| 50 °F | 10 °C | Cool autumn day |
| 59 °F | 15 °C | Standard temperature for thermodynamics (ISO 13443) |
| 68 °F | 20 °C | Room temperature (common reference, ASHRAE comfort range) |
| 72 °F | 22 °C | Indoor comfort |
| 77 °F | 25 °C | STP (semiconductor industry), warm room |
| 86 °F | 30 °C | Hot summer day |
| 98.6 °F | 37 °C | Human body temperature (oral, healthy) |
| 100.4 °F | 38 °C | Low-grade fever threshold |
| 104 °F | 40 °C | High fever; hot tub max |
| 113 °F | 45 °C | Hot day in Death Valley / Persian Gulf |
| 134 °F | 56.7 °C | Highest recorded air temperature on Earth (Death Valley, 1913 — WMO official record) |
| 140 °F | 60 °C | Hot water supply (max) / safe holding temperature for food |
| 165 °F | 74 °C | Safe minimum internal temperature for poultry (USDA) |
| 180-205 °F | 82-96 °C | Coffee brewing (drip / pour-over range) |
| 212 °F | 100 °C | Water boils (1 atm) |
| 350 °F | 175 °C | Standard baking (gas mark 4) |
| 375 °F | 190 °C | Hot frying oil |
| 400-450 °F | 200-230 °C | Pizza, breads (gas mark 6-8) |
| 572 °F | 300 °C | Auto-ignition temperature of paper |
| 621 °F | 327.5 °C | Lead melts |
| 1220 °F | 660 °C | Aluminum melts |
| 1984 °F | 1084.6 °C | Copper melts |
| 2192 °F | 1200 °C | Industrial brazing (silver) |
| 2730 °F | 1500 °C | Steel melts (varies by alloy) |
| 6192 °F | 3422 °C | Tungsten melts (highest melting metal) |
| 6692 °F | 3700 °C | Carbon arc temperature |
| ~10,000 °F | ~5500 °C | Surface of the sun |
About 'standard temperatures'. Different fields use different reference temperatures: 0 °C / 32 °F for ice point; 20 °C / 68 °F for ASHRAE 'room temperature'; 25 °C / 77 °F for semiconductor 'STP'; 15 °C / 59 °F for natural gas STP (ISO 13443); 20 °C and 100 kPa for IUPAC STP since 1982. Always check which 'standard' your reference document means.
Common applications
| Cooking temperature (°F) | (°C) | What it's for |
|---|---|---|
| 140 °F | 60 °C | Steak: medium rare |
| 145 °F | 63 °C | USDA safe minimum: whole cuts of beef, pork, lamb |
| 150 °F | 65 °C | Steak: medium |
| 160 °F | 71 °C | Ground beef safe internal temperature (USDA) |
| 160 °F | 71 °C | Steak: medium well |
| 165 °F | 74 °C | Poultry safe internal temperature (USDA) |
| 170 °F | 77 °C | Coffee brewing minimum (some methods) |
| 180 °F | 82 °C | Drip coffee, tea (green tea) |
| 190 °F | 88 °C | Tea (oolong, white) |
| 200 °F | 93 °C | Tea (black, herbal); espresso brewing temperature |
| 212 °F | 100 °C | Boiling water (sea level) |
| 350 °F | 177 °C | Standard baking temperature |
| 375 °F | 190 °C | Hot oil for shallow frying |
| 400 °F | 204 °C | Roasting vegetables; bread |
| 450 °F | 232 °C | Pizza, hot-temperature roasting |
| 500 °F | 260 °C | Pizza stone, very hot |
Common pitfalls
- Boiling point depends on pressure. Water boils at 100 °C at sea level (1 atm). At 5,280 ft elevation (Denver), water boils at about 95 °C / 203 °F. At the top of Mt. Everest, around 70 °C / 158 °F. This affects cooking times and is why pressure cookers work.
- Body temperature isn't exactly 37 °C. Healthy oral temperatures range from 36.1 to 37.2 °C (97-99 °F), with diurnal variation. Rectal temperatures run about 0.5 °C higher; axillary (armpit) about 0.5 °C lower. '98.6 °F' is an average, not a rigid number.
- 'Room temperature' isn't standardized. ASHRAE comfort range is 68-76 °F (20-24 °C) depending on humidity, season, and activity. Scientific 'room temperature' is often 20 °C (68 °F) or 25 °C (77 °F) depending on the field.
- Fan ovens run hotter than conventional. A recipe at 180 °C (350 °F) conventional should be 160 °C (320 °F) on a fan-assisted oven — about 20 °C / 35 °F cooler.
- USDA safe-food temperatures are higher than European equivalents. The US specifies 165 °F (74 °C) for poultry; UK / EU often accepts 70 °C (158 °F) if held for time. Both produce safe food if held for the appropriate time, but US guidance is more conservative.
Common questions
Why does the Fahrenheit scale have 32° for freezing instead of 0°?
Fahrenheit's 1724 scale set 0°F to the freezing point of a brine (water + salt) — the coldest stable temperature he could reproduce. Then he set 96° to human body temperature (later refined to 98.6°F). Water freezing at 32°F and boiling at 212°F became fixed points after recalibration. The scale's only modern advantage: weather temperatures rarely go below 0°F.
What's absolute zero and why does it matter?
Absolute zero is -273.15°C / -459.67°F / 0 K — the temperature at which molecular motion stops. Below this is physically impossible. It matters because thermodynamic equations (gas laws, entropy) use absolute temperature. Tripling absolute temperature triples pressure or volume at constant conditions; tripling Celsius does not.
Why is human body temperature 98.6°F (37°C) and not 100°F?
Historical reasons. Fahrenheit originally set 96°F as 'blood-heat'. Later measurements with better instruments put healthy body temperature at 98.6°F (37°C). It's actually a range: 36.5-37.5°C is normal, and varies by time of day, individual, and measurement site.
How hot does a kitchen oven actually reach?
Residential ovens reach 260-290°C (500-550°F) on bake mode, up to 290-315°C (550-600°F) on broil. The actual temperature swings ±15°C around the set point as the heating element cycles. Older ovens drift more. For accurate baking, an oven thermometer reveals the truth — and the cycling is why baking time varies.
What's the hottest natural temperature on Earth's surface?
Officially: 56.7°C (134°F) at Furnace Creek, Death Valley, CA on July 10, 1913. Surface temperatures of dark surfaces in direct sun have been measured up to 80°C (176°F), but those aren't air temperatures. Higher claimed temperatures (58°C in Libya, 1922) were later invalidated by the World Meteorological Organization.
Sources
- Absolute zero, water phase points: Defined in ITS-90 (International Temperature Scale of 1990).
- STP definitions: IUPAC (100 kPa, 0 °C); NIST (101.325 kPa, 20 °C); ISO 13443 for natural gas (15 °C); semiconductor industry (25 °C).
- Cooking safe temperatures: USDA Food Safety and Inspection Service guidelines.
- Comfort temperatures: ASHRAE Standard 55 — Thermal Environmental Conditions for Human Occupancy.
Disclaimer. Cooking and food-safety temperatures should be verified against the most current USDA or local health-authority guidance. Industrial reference temperatures depend on the field — always confirm the relevant standard.